1. Field of the Invention
This invention relates to magnetic tape recording heads, and more particularly to a tape recording head having low transducer and gap recession due to tape wear.
2. Description of the Related Art
In magnetic storage systems, data is read from and written onto magnetic recording media utilizing magnetic transducers commonly referred to as magnetic heads. Data is written on the magnetic recording media by moving a magnetic recording head to a position over the media where the data is to be stored. The magnetic recording head then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read head and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has lead to increasing the track density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, magnetic tape is moved over the surface of the tape head at high speed. This movement generally entrains a film of air between the head and tape. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial so that the recording gaps of the transducers, which are the source of the magnetic recording flux, are in intimate or near contact with the tape to effect efficient signal transfer, and so that the read element is in intimate or near contact with the tape to provide effective coupling of the magnetic field from the tape to the read element.
A flat contour thin film tape recording head for a bi-directional tape drive is described in commonly assigned U.S. Pat. No. 5,905,613 to Biskeborn and Eaton which is incorporated by reference herein. The flat contour head comprises a flat transducing surface on a substrate having a row of thin film transducers formed on a surface on one side of the substrate which forms a gap. The substrate with the row of transducers is called a “rowbar substrate”. The transducers are protected by a closure of the same or similar ceramic as the substrate. For a read-while-write bi-directional head which requires that the read transducer follows behind the write transducer, two rowbar substrates with closures are mounted in a carrier facing one another. The recording tape overwraps the corners of both substrates and closures with an angle sufficient to scrape (skive) the air from the surface of the tape and not so large as to allow air to reenter between the tape and the transducing surface after the tape passes the corner. By scraping the air from the surface of the moving tape, a vacuum forms between the tape and the flat transducing surface holding the tape in contact with the transducing surface. At the corners of the air skiving edge, bending of the recording tape due to the overwrap results in separation of the tape from the transducing surface for a distance that depends on the wrap angle, the tape thickness and the tape tension. The transducers must be spaced from the corners of the air skiving edges at a sufficient distance to allow the vacuum between the tape and the transducing surface to overcome this separation.
Recession of the transducers in the gap between the hard ceramic substrate and closure due to tape wear is a problem that results in increased spacing loss of the readback signal. Efforts to minimize gap erosion in hard disk drive type ceramic tape heads usually involves making the gap materials more wear resistant or coating the head with wear resistant material. Transducer materials must have specific magnetic properties which greatly limits the search for materials having both good magnetic and mechanical properties. Coatings may eventually wear off and/or cause unacceptable spacing loss.
There is an ongoing need for a tape recording head having reduced recession of the transducers to improve reliability and component life. The present invention provides an improved recording head to address this need.